On Fri, 02 Dec 2011 12:38:33 -0600, Tim Wescott
wrote:

On Fri, 02 Dec 2011 08:47:33 -0800, Jon Anderson wrote:

Had a brochure years ago for a company that made worm wheels cut to use
standard threaded rod for the worm. Can't find it now. I might well end
up making my own, but at least want to see (if they're still around)
what an off the shelf worm wheel would cost.

Anyone run across, and remember the name of this outfit?

I'm guessing he

I think that such an assembly would be even more inefficient than a worm
drive. Additionally, it seems that getting proper mesh would be
problematic: a worm gear will have a sort of flat-ish spot that'd give
you a nice broad optimum, while a V-cut would require that you get
everything just right to work. Moreover, the V-cut would tend to always
want to push the gears apart, to a greater extent than a normal worm gear
tooth profile -- put that together with the extra need for accuracy, and
it'd be difficult to keep your assembly in tune.

It sounds like one of those deals that's just too good to be true.


I've made several of these things on my lathe with the milling
attachment. One of them is in use right now, on my fishing-rod
rotisserie, which I use for getting the layer of epoxy evenly
distributed on guide windings.

If you're in need of a light-duty worm gear, they work fine. You
chuck an ordinary thread tap in the lathe spindle. First turn a blank
for the gear in the lathe, drilling and boring a hole in the center
for a temporary spindle.

I've used a bolt for the spindle, polishing it up a bit on the lathe.
Chuck the spindle with gear blank in the milling attachment vise (you
can clamp it in a toolpost if you don't have a milling attachment).
Feed the edge of the gear into the rotating tap until it starts to
cut. It will self-feed.

If' you're lucky, it will cut clean, or nearly so, all the way around
the blank. If it's a little rough, keep feeding the blank into the tap
until you get a clean cut. You may have to turn a little bit off of
the blank's periphery to get a clean cut all the way around.

That's all there is to it. If you need an exact number of teeth on the
gear, forget about it. d8-)

--
Ed Huntress